How to Tell if a Stick Insect Has Changed Color

We used to have stick insects on ours, a cat and stick. Maybe they were just trying to get themselves thrown up. What's a poo look like from a stick insect? It's just like a black dot. Can the leaf insects change color in the autumn? I don't think so. And if you stimulate the insect's mouth pelps, which these small organs near the mouth, which are incredibly sensitive - it will make a sudden movement. If not, it has died.